1. Field of the Invention
The present invention relates to an outboard motor and an oil pan unit for an outboard motor, and more particularly, it relates to an outboard motor and an oil pan unit for an outboard motor each including an oil pump.
2. Description of the Related Art
An outboard motor including an oil pump is known in general. Such an outboard motor is disclosed in Japanese Patent Laying-Open No. 2009-102993, for example.
Japanese Patent Laying-Open No. 2009-102993 discloses an outboard motor including an engine including a plurality of cylinders and a crankshaft, a drive shaft coupled to the crankshaft and configured to transmit the rotational power of the crankshaft, an oil pan provided below the engine, an oil pump driven by the crankshaft, and a supply path configured to supply oil from the oil pump to the engine. In the outboard motor according to Japanese Patent Laying-Open No. 2009-102993, the oil pump is arranged above the oil pan and sucks up oil from the oil pan to supply the oil to the engine.
In the outboard motor according to Japanese Patent Laying-Open No. 2009-102993, the oil pump is provided above the oil pan, and hence a path to suck up the oil from the oil pan is required. When the length of this path is increased, a time from when the oil pump is driven until when oil is supplied to the engine (hydraulic pressure rise time) is increased. The path of oil is required to be configured such that priming oil for sucking up oil from the oil pan when the oil pump is started remains, and hence the structure of the path is complicated. Therefore, it has been desired to simplify the structure of the path of oil and to reduce the time from when the oil pump is driven until when oil is supplied to the engine (hydraulic pressure rise time).
In general, an outboard motor in which an oil pump is provided below an oil pan has also been disclosed. Such an outboard motor is disclosed in Japanese Patent Laying-Open No. 05-052107 (1993), for example.
Japanese Patent Laying-Open No. 05-052107 discloses an outboard motor including an oil pump arranged below an oil pan and configured to be driven by a drive shaft. In the outboard motor according to Japanese Patent Laying-Open No. 05-052107, the oil pump is spaced apart and below the oil pan through a pipe coupled to a lower end of the oil pan and a strainer.
In the outboard motor according to Japanese Patent Laying-Open No. 05-052107, however, the oil pump is spaced apart and below the oil pan, and hence the length of a supply path from an oil discharge port of the oil pump to an engine located on the upper side is disadvantageously increased. Thus, a time from when the oil pump is driven until when oil is supplied to the engine (hydraulic pressure rise time) is disadvantageously increased.